Suppose I have a million dollars. Could I make a fab [1] that can manufacture a Intel 286 processor (with feature size roughly 1.5 micrometer) or equivalent? If not, what year of semiconductor manufacturing technology could I replicate?
Sam Zeloof [1] is a high school student who produced an integrated circuit in his garage. He says that the gate size is 175μm, but he has produced test features as small as 2μm. Looking at the photos of his lab, he has probably invested tens of thousands of dollars in the project.
Also, check LibreSilicon [1], a free and open source semiconductor manufacturing process, currently in development. The target is 1 μm, but the developers said 0.5 μm should be possible. Here's a comprehensive introductory talk [2]. And as usual, the project is on GitHub [3]. If things went well, they said they planned to manufacture an open source RISC-V microcontroller, pin-compatible with Atmel AVR ATTiny.
University labs often have cleanrooms that definitely do cost roughly on the order of low millions. And they are built to the standards of 2010s fabrication requirements. Replicating 1980s cleanroom requirements today would be a lot cheaper.
Edit: Page 64 of the pdf https://dokumente.unibw.de/pub/bscw.cgi/d9262701/01_History.... suggests in 1980 the total investment cost of a fab was $100million. I would expect that same tech could be replicated a lot cheaper today. A 100x improvement doesn't seem outrageous.
I don't see anything on that slight that indicates whether the numbers are inflation-adjusted or not. $100million in 1980 dollars is ~$300million in 2019 dollars. That's going to eat into your savings quite a bit.
I'm no expert, but a 100x savings seems pretty outrageous to me and 300x even more so.
Wikipedia provides this rough estimate of feature size - year table: 10 µm – 1971 6 µm – 1974 3 µm – 1977 1.5 µm – 1982 1 µm – 1985 800 nm – 1989 600 nm – 1994 350 nm – 1995
What about only a 100K USD?
[1] capital costs only. Not labor.